Answer:
The correct option is (b).
Step-by-step explanation:
If X
N (µ, σ²), then
, is a standard normal variate with mean, E (Z) = 0 and Var (Z) = 1. That is, Z
N (0, 1).
The distribution of these z-variate is known as the standard normal distribution.
The mean and standard deviation of the active minutes of students is:
<em>μ</em> = 60 minutes
<em>σ </em> = 12 minutes
Compute the <em>z</em>-score for the student being active 48 minutes as follows:

Thus, the <em>z</em>-score for the student being active 48 minutes is -1.0.
The correct option is (b).
1. Start by identifying what the question wants so we are looking for miles per 1 gallon.
2. Set up a statement. When the word “per” is being used it relates to a fraction or a ratio. In this question we need to find how many miles a single gallon will give us. So set it up as miles/gallons
3. Plug in your numbers. Now our statement is 13 miles/15 gallons
4. Calculate. So do 13/15 which equals 0.86 miles per 1 gallon.
Tip: always add in words into your calculations. Mainly the units you are using so you can quickly look and know what the units will be. This will help you in upper placement math as well
That condition is true if P(A) and P(B) are independent of one another. For example, if I was pulling marbles out of a bag, if I am replacing the marbles back after I pull one out, then P(A or B) = P(a)+P(B).
In pythagoras's theorem, generally a is the shortest side, b is the second shortest and c is the hypotenuse:

. However, there is a problem. The questions aren't actually possible without using sine, cosine, and tangent (which are mathematical ratios if you didn't know). I can help you with this but it will take time explaining.